Recently, a variety of optical discs have been proposed as disc-shaped recording mediums that are recordable and that can be dismounted from a recording and/or reproducing apparatus. These recordable optical discs have been proposed as large-capacity mediums of several GBs and are felt to be promising as mediums for recording AV (audio visual) signals, such as video signals.
Among the encoding systems for digitally compressing digital video signals, there is an MPEG (Moving Picture Experts Group) 2 system. The MPEG2 is also finding application in recording digital video signals on recording mediums. For example, in recording digital video signals on a recording medium, the video signals are encoded in accordance with the MPEG2 system to record an encoded bitstream on a recording medium. In the digital television (TV) broadcast, which recently made its debut, a video program, encoded in accordance with the MPEG2 system, is transmitted in accordance with the format termed a transport stream. In recording the digital broadcast on an information recording medium, such a system is used in which the transport stream is recorded in the form of digital signals, without decoding or re-encoding.
If AV signals are recorded on a recording medium, random access reproduction, such as locating or fast-feed reproduction of AV signals, can be realized readily. Using this feature, it is possible for a user to select an optional reproduction domain, specified by an IN point (in-point) and OUT point (out-point) from the recorded AV signals to formulate the playback route of the AV signals freely. This function is routinely termed a play-list reproduction. For example, in the DVD recording standard (DVD specifications for Rewritable/Re-Recordable Discs, Part 3 Video Recording, Version 1.0, September 1999), the playlist reproduction is prescribed as PGC or Original PGC.
The user is also able to select a start point of a favorite scene to record the reproduction information on the locating point information. This function is termed a characteristic point or a mark and, in, for example, the DVD video recording standard, the function is prescribed as being the Movie Cell Entry Point Information (M_C_EPI).
If, in case the user has selected an optional reproduction domain (start and end points) from a given playlist, a function which affords a particular meaning to the reproduction domain is to be implemented, the following two methods may be contemplated.
The first method is such a method in which, in case a user has selected the specified playback domain from the playlist, a separate playlist, having the playback domain as a playback route, is prepared. This method suffers from a drawback that the number of playlists is increased even although the user is not desirous to prepare separate playlists.
The second method is such a method in which, in case a user has selected the specified playback domain from the playlist, the domain so selected is indicated using two marks, namely a start mark and an end mark. This method, however, suffers from a drawback that not only the number of the mark information is increased but also the reproducing or editing operation employing the mark is complicated because the two marks representing the domain must be managed as a pair.
If a moving picture of an optional characteristic moving picture is selected from the input AV stream, and a function which accords a particular meaning to the domain is to be implemented, such a method may be envisaged in which the domain is indicated by, for example, two marks, namely a start mark and an end mark. This method, however, suffers from a drawback that the number of the mark information is increased, and that, since the two marks indicating the domain must be managed as a pair, the management method for mark recording and/or reproduction tends to be complicated.